We are All Part of the Same Ecosystem

Tropical regions, with their high temperatures and high levels of rainfall, provide ideal conditions for the life and growth of plants. It is said that two-thirds of the numbers of species of plants which exist on earth are found in tropical rainforests. The diversity of plants is also matched by an extensive variety of animals and fungi. The intricate structure of tropical rainforests, though, is poorly understood and we still know almost nothing about the life forms in the canopy, the top layer of such forests. 

In the wetlands of cold northern regions, the remains of plants fail to decompose and instead become compressed to form layers of peat. The life forms found in these regions have adapted in remarkable ways to deal with in their local environment, which may contain excess water, low temperatures, and insufficient nutrients. The conditions of wetlands, though, are not stable. They are continually moving towards forestation as a result of sedimentation of soil and nutrients, the remains of undecomposed plants, brought in from surrounding areas.

Temperate deciduous forests display all the colors of all four seasons. The various forms of life in these forests have special adaptations to cope with extremes of the changing seasons. The thick layer of fallen leaves are decomposed by fungi and soil organisms, providing a fertile foundation for a variety of life.

Having exceptionally little rainfall, the Taklamakan Desert, the largest desert in Asia, presents an extremely challenging environment for life forms. Organisms found here make the best possible use of the limited water resources and endure severe conditions of aridity and high concentration of salt deposition.

What is a species? A species is a unit defined by ecological position and reproduction. A species is the basic unit in the demarcation of living organisms. The habitat and feeding habits are specific to species. In terms of reproduction, each species is maintained by interbreeding within their own species. A species is thus grouped by ecological status and reproduction. It should be noted, though, that it can be difficult to differentiate species simply by their appearances.

Variations within species can lead to Evolution. Even within the same species, many differences may be found among the individuals. Such differences are referred to as "individual variation". This variation often has a genetic background, resulting from genetic mutations. Among the individuals with such variations, those who fit better into the environment survive more often. This is what is know as "natural selection", and after generations, the genetic composition of the population changes. Mutations and natural selection are the prime factors in driving evolution.

Inhibition of interbreeding will result in diversification. Speciation is  a term which refers to the emergence of a separate species from a parent species. This development of new species has resulted in the diversification of life. Since a species is defined as a population in which interbreeding is possible, a speciation means the emerging new group of individuals that cannnot interbreed with members of the original group, hence the establishment of reproductive isolation. It is believed that when breeding among groups of the same species is blocked, reproductive isolation is eventually formed, and this leads to the speciation.

Extraordinary diversification. Organisms exist that are extremely diverse in appearance and ways of life, although closely related to one another. Such organisms have developed, or are in the process of developing, into different species for various environments. These organisms are merely a small portion of the vast variety of life forms, and their continual appearance indicates that the diversity of life which covers Earth is not yet well understood.

From bacteria to humans, the number of species that now exist on earth is at least 1.6 million. These species show great diversity, which has resulted from repeated branching of new evolutionary lines from ancestral forms inhabiting ancient oceans. All forms of life are ultimately related to one another, as shown by the Tree of Life.

Monstrous versus tiny. Size of the body is clearly related to the strategy of survival. Major different animals depending on their species or ways of life. Such differences provide hidden indications of the many ways such animals have become adapted to live in specific environment. The mechanisms underlying body structures which have evolved into different shapes and sizes to develop, and the ways of life which result from those differences could be a source of the variety of life.

From desert to polar regions, organisms adapt to the fierce environments they face. There are some forms of life which live in harsh environments such as deserts, high altitudes, or polar regions. Such creatures are equipped with special mechanisms within their bodies which enable them to live even with scarce water or extreme high or low temperatures. Such mechanisms have enabled life forms to evolve into many varieties of forms which have occupied all environments of Earth.

Various ways of getting nutritions. It is by seeking for different sources of nutrients on Earth that living organisms have been able to survive and spread throughout the diversified natural environment. The key to survival lies in where one can find food and in how one can find a new source of nutrients. The physical mechanisms and ways of life of different life forms which have been developed in order to obtain nutrents are surprisingly diverse.

How do organisms overcome the tough task of successfully leaving descendants? The physical structure and ways of life of different organisms are designed especially to allow them to prosper. Two reproductive strategies have developed : to give birth to numerous or to few offspring. Behaviorial encounters between males and females also influence success rate. The females also influence success rate. The result is a trial- and-error operation in which each living organism tries to outcompete others to leave its next generation.